As it's that time of year I thought it is time for a Santa themed question...
Keeping the bureaucracy up to date with one's correct address is a nightmare: recently I have experienced it firsthand, when a credit recovery agency contacted me for not having paid taxes during the past 3 years in a city where I do not reside for more than 5 years. It has taken some struggle to prove that I didn't owe any taxes because I had legally moved to another city.
Apparently, Santa is immune to this struggle: presents are always timely and precisely delivered, even if little Sarah and Tommy have moved to their new place in Middleofnowhereton with the family the night before. And all of this way before we all had GPS equipped devices allowing us to be (potentially) tracked with meter precision.
This of course begs the question: how can Santa, since the times of Victorian era, be able to keep updated logs of the location of all the kids who will be getting a present from him?